Exposure to THC during pregnancy affects fetal development, new study shows

Researchers at Western University and Queen's University are the first to find a link between cannabis use during pregnancy and low birth weight babies.

The research backs up clinical studies that found cannabis use is linked with low birth weights

It's believed the study is the first to show a link between cannabis use during pregnancy and low birth weight babies. (The Canadian Press)

Regular cannabis use during pregnancy has a significant impact on placental and fetal development, according to a new study conducted by researchers at Western University and Queen's University.

The study, published in the journal Scientific Reports, found regular exposure to low doses of THC during pregnancy led to a reduction in birth weight by eight per cent, and decreased brain and liver growth by more than 20 per cent. 

"This is the first study to definitively support the fact that THC alone has a direct impact on placental and fetal growth," said Dan Hardy, a Western associate professor and co-author of the study.

THC is the main psychoactive ingredient found in cannabis. 

Researchers used a rat model and human placental cells, and applied small doses of THC that would mimic daily use of cannabis during pregnancy.

They noted THC prevented oxygen and nutrients from crossing the placenta into the developing fetus. 

In particular, THC decreased the levels of GLUT-1, a transporter responsible for sending glucose from the mother to the fetus. 

"This data supports clinical studies that suggest cannabis use during pregnancy is associated with low birth weight babies. Clinical data is complicated because it is confounded by other factors such as socioeconomic status," Hardy said.



Alvin Yu

CBC staff

Alvin Yu is an associate producer, senior writer and social editor/presenter for CBC News: The National. Yu set his sights on journalism early — as a kid, he would anchor the news in the shower, hoping one day to make it to the big screen.